Television transmission method



G. SCHUBERT 2,079,880

TELEVISION TRANSMISSION NETHOD May 11, 1937.

Filed June 27, 1935 lnventor:

Patented May 11, 1937 UNITED STATES PATENT OFFICE firm Fernseh Aktien-Gesellschaft, Zehlendorl,

near Berlin, Germany Application June 2'7,

1933, Serial No. 677,932

In Germany June 30, 1932 6 Claims.

This invention relates to atelevision transmission method intendedprimarily for the transmission of animated scenes, in which transmissionis performed with the assistance of an intermediate record prepared on anormal motion picture film. Immediately following exposure the film isdeveloped in a rapid developer and passed through a transmissionapparatus, which performs the transmission within a very few secondsafter the actual incident has taken place.

I have already describedv a method of this nature in my copending patentapplication Ser. No. 641,092 filed Nov. 3, 1932.

In order to televise a scene of long duration without interruptions itwould be necessary to employ film reels of correspondingly large size.Thus, for example, for a transmission lasting 30 minutes approximately3,000 feet of film would be required. Although this to a certain extentwill be found sufllcient for the transmission of short scenes, it maynevertheless be desired or necessary that transmissions of greaterduration are provided. In this case it would be necessary to introducerelatively long intervals into the transmission for the purpose ofexchanging the film reels and inserting the new length of film into thetransmission apparatus.

It is the object of the invention to overcome the drawback in question,and this is accomplished by the use of two transmission apparatusoperating alternately. When changing over from one apparatus to theother, care must be taken above all that the transmission of the imagecontinues in the same phase as in the apparatus which has beendisconnected, as otherwise a readjustment of the phase of alLreceivgrswill be necessary.

This problem may be solved in different ways. Preferably the procedurewill be such that the transmission apparatus 200 is set into operation acertain time before disconnection of the transmission apparatus I00, andin the first place acts on a control receiver, which runs absolutelysynchronously with and in the same phase as the control receiverpertaining to the transmission apparatus I00. Assuming, for example,there is employed as control receiver a receiver of the Nipkow disctype, the mode of operation for this purpose may be such that theoperating motor for the control receiver belonging to the apparatus I00is coupled by means of a flexible shaft with the operating motor for thecontrol receiver belonging to the transmission apparatus 200. In thiscase the discs runabsolutely synchronously and with equal phase.

A more simple method consists in mounting the two Nipkow discs, whichserve for composing the two received images, on a common shaft, and inthis way combining the control receiver of the apparatus I00 with thecontrol receiver of the apparatus 200. It is, however, also possible touse only one Nipkow disc if, for example, the same is provided with twospirals and supplies two control images simultaneously, of whichadmittedly one is somewhat larger than the other. Complete equality inthe size of images may be obtained by corresponding adjustment of theoptical enlargement means. is possible to work with control receivers ofother systems which for example employ Braun tubes.

The change over from the transmission apparatus I 00 to the apparatus200 takes place in such form that, asalready described, the apparatus200 is set into operation a certain time before the apparatus I00, isdisconnected the apparatus 200 produces now at the control receiver animage, the phase of which initially is not correct in relation to theimage supplied by the apparatus I00. In order to equalize the phase ofthe two images .it is necessary to vary the phase of the filmadvancingmotor of the apparatus 200 until the phase of the two control images isexactly the same. As soon as this condition has been attained theapparatus I can be disconnected, and there the apparatus 200 is employedfor modulation of the wireless. transmitter. This change overoperation-will hardly be perceptible by the person at the receiving end.

In order to make the disconnected apparatus I00 again ready foroperation with the least possible delay it is desirable to disconnectthis apparatus at the moment when the end of the film leaves the supplyreel so that a new film may be secured to the end of this film beforeitis drawnthrough the various parts of the apparatus. There is always acertain length of film present in the complete transmissionapparatus, 1. e., in the camera, the lightproof apparatus fordevelopingand fixing the film, the image-scanning apparatus and thevarious passages or ducts connecting these parts. This piece of filmsituated in the apparatus may be -25 feet long. If now specialprecautions were not taken, it might happen that upon disconnection ofthe apparatus I00 the end of the film runs into the one or the otherapparatus serving for the photo-chemical processes or into theimage-scanning apparatus.

This is extremely undesirable, because it would then be necessary tothread the new film manually through the entire apparatus, which is avery tedious operation,as it is necessary to open both In similar mannerit the camera as well as the developing and fixing apparatus in order topass the film through the different guiding elements, which in part aresituated in liquid. The film also would have to be introduced into theoperating and guiding elements of the image-scanning device, and securedto the hub of the storage reel. Since this manual threading operationmoreover is accompanied by a readjustment of all film wiping means, aconsiderable time would elapse before the apparatus is again ready foruse.

To avoid these difiiculties the apparatus I00, according to theinvention, is stopped shortly before the end of the film leaves thesupply drum, and the leading end of the new film is connected with theend of the old film, by the usual cementing process. In this manner amanual insertion of the new film is avoided, as the end of the old filmguides the leading end of the new film automatically into the apparatus.Proper use of this method however depends upon careful attention on thepart of the operator, who also has to start the apparatus 200 in goodtime before the film in apparatus I00, is exhausted. Simultaneously withthe disconnection of apparatus I00 the transmission apparatus 200 mustbe switchedover on to the amplifier. Even assuming that the unwindingfilm on the apparatus I00 is observed with the assistance of a graduatedrevolution indicator, errors may readily occur upon disconnection of theapparatus I00 and change over on to apparatus 200.

To overcome these difficulties the present invention provides means forperforming the various switching operations automatically. At apredetermined time before the end of the film on apparatus I00 leavesthe supply reel an optical or acoustical signal is set in operation bythe closing of an electrical contact. This contact is automaticallyclosed when the diameter of the film spool on the reel has decreased toa predetermined size. This contact may consist, for example of aresilient push button. The signal notifies the operator to start theapparatus 200 and to adjust the same correctly according to phase. Atthe moment when the last winding of film leaves the hub of the supplyreel the apparatus I00 is disconnected automatically, and by means ofthe same actuating element the apparatus 200 is changed over on to thetransmission amplifier. In this manner all difficulties are avoided whenchanging over from apparatus I00 to apparatus 200.

The invention is illustrated diagrammatically by way of example in theaccompanying drawing.

The two transmission apparatuses I00 and 200 are operated through themedium of the synchronous motors IN and 20| by the same current supply3. The two apparatuses are adapted to be connected selectively by meansof the relay 40 with the transmission amplifier 5, with which there iscoupled the aerial 6 in the known manner.

The actuating relay 40 comprises the contact lever 4|, pivoted at 42,and resting against either one of the contacts I02 and 202 pertaining tothe transmitters I00 and 200 respectively.

The actuation of the contact lever 4| takes place electro-magneticallywith the assistance of the solenoid 43, which when energized attractsthe iron core 44 connected with the lever 4|. When on the other hand thecurrent through the solenoid is interrupted, the lever 4| and the ironcore 44 connected therewith is withd awn i qm the solenoid 43 by thespring 45. When, therefore, the solenoid 43 is energized thetransmission apparatus 200 will be connected with the transmissionamplifier, and when no current passes through the solenoid 43 theapparatus I00 will be connected with the amplifier. As alreadyindicated, the relay is actuated by means co-operating with the filmspool in the transmission apparatus. In the drawing these actuatingmeans are shown in the form of contacts I03 and 203, which arecontrolled by the film spool on the reel I04 and 204 respectively.

The contact 203 is closed as long as there is a film wound upon the reel204. The contact 203 opens, however, automatically in the moment thelast end of the film leaves the reel 204. The contact I03, however, isopen when the reel I04 has wound thereon a film and this contact closesautomatically in the instance when the last end of the film leaves thereel I04. The solenoid 43 is provided with two windings 5| and- 52 andcontains a contact 50 which is opened and closed simultaneously with thecontact 202. The operation of the relay 40 is as follows:

It be assumed that the apparatus I00 is in operation and the filmunwinds from the reel I04 while a new film is ready for use on the reel204 of the apparatus 200. Under this condition the contact I03 is openand the contact lev'er 4| due to the action of the spring 45 is pulledto- Ward the right hand side in engagement with the contact I02, so thatthe circuit of the contact 203 is open, even though the contact 203itself is closed. As soon as the last end of the film leaves the reel I04 the contact I03 is automati- 1 previously has been set in operationby the operator, is connected with the transmission amplifier 5, whileowing to the opening of the contact I02 the apparatus I00, of course, isdisconnected from the amplifier 5.

During the operation of the apparatus 200 a new film can be convenientlyloaded into the apparatus I00, whereby the contact I03, of course,

is again opened, but this does not in any way in-- terfere with theoperation of the apparatus 200. When the last end of the film in theapparatus 200 leaves the reel 204 the contact 203 is opened and sincethe contact I03 is already open both windings of the solenoid 43 arede-energized and the spring 45 draws the armature 44 toward the righthand side in which the contact lever 4| engages the contact I02, therebyagain connecting the apparatus I00 with the amplifier 5. In this waythe-apparatus I00 and 200 are alternately. connected automatically withthe transmission amplifier 5, it is only necessary to replace in theapparatus which has been disconnected from the amplifier 5 the emptyreel by a reel on which a new film has been wound; This can easily bedone while the other apparatus is in operation.

The control receivers for adjusting the correct phase of thetransmission system consist of the receivers I I0 and 2 I0, whichcontrol in the known and H2 which, for maintaining the synchronous run,are preferably rotated by the same motor I i3 there is produced in theknown fashion 'an image, which may be observed by the operator either atthe point H4 or at the point 2". The

regulation of the correct phase position is performed by the knownmeans, for example by varying the position of the stator, of theoperating motors |I0l or 2M.

What I claim as new and desire to secure by Letters Patent is 1. In atelevision method, employing a motion picture film, the steps ofsuccessively subjecting a plurality of motion picture films to ascanning operation while the films are in motion, starting eachsucceeding film while the preceding film is still in motion so that bothfilms then move simultaneously, transmitting the images, on the films byelectrical currents representative of said scanning, synchronizing themovement of the two films during this period of simultaneous motion,adjusting during the same period the phase position of the image of thesucceeding film to be in the same phase as the image of the precedingfilm, and discontinuing transmission of the preceding film andsimultaneously taking up transmission of the succeeding film, as soon assynchronism and phase equalization has been established.

2. The method of televising an animated scene comprising the steps ofsuccessively and continuously producing a plurality of moving picturefilms from said animated scene, immediately subjecting each filmsuccessively while in motion to a scanning operation, and' transmittingthe images on the films by electrical currents representative of saidscanning, starting each succeeding film while the preceding film isstill in motion so that both films then move simultaneously,

synchronizing the movement of the two films during this period ofsimultaneous motion, adjusting during the same period the phase positionof the image of the succeeding film to be in the same phase as the imageof the preceding film,

- and discontinuing transmission of the preceding film andsimultaneously taking up transmission of the succeeding film as soon assynchronism.

and phase equalization has been established.

3. In a television system in which motion pic-' ture films are used assuccessive intermediate transmission members, including a plurality oftransmitting apparatuses each being adapted to subject a motion picturefilm while in motion to a scanning operation, each transmittingapparatus being adaptedto transmit the images on the film by electricalcurrents representative of said scanning, a single transmissionamplifier adapted to be alternately connected with said transmissionapparatuses, means controlled by the motion picture film in each of saidtransmission apparatuses for automatically connecting the transmissionamplifier with the next transmission apparatus when a predeterminedlength of the film in the transmission apparatus connected with theamplifier has been transmitted, and control receivers, one beingconnected with each transmission apparatus for synchronizing themovement of successive films during a period of simultaneous motion oftwo films during the operation of two successive transmittingapparatuses incident to starting the succeeding film while the precedingfilm is still in motion, said control receivers being adapted to adjustduring this period the phase position of the succeeding film to be inthe same phase as the image of the preceding film. v

4. In a television system in which motion picture films are used assuccessive intermediate transmission members, including two transmitting apparatuses each being adapted to subject a motion picture filmwhile-in motion to a'scanning operation, each transmitting apparatusbeing adapted to transmit the images on the film by electrical currentsrepresentative of said scanning, a single transmission amplifier adaptedto be alternately connected with said transmis-. sion apparatuses, meanscontrolled by the motion picture film in each of said transmissionapparatuses for automatically connecting the transmission amplifier withthe other transmission apparatus when a predetermined length of the filmin the transmission apparatus connected with the amplifier has beentransmitted, and control receivers, one being connected with eachtransmission apparatus, a scanning disc for each control receiver, asingle drive shaft on which both of said scanning discs are fixedlymounted 'for simultaneous rotation, said control receivers beingprovided for synchronizing the movement of successive films during aperiod of simultaneous motion of two films during the operation of saidtransmitting apparatuses incident to starting the succeeding film whilethe preceding film is still in motion, said control receivers beingadapted to adjust during this period the phase position of thesucceeding film to be in the same phase as the image of the precedingfilm.

5. In a television method employing a motion picture film, the steps ofsuccessively subjecting a plurality of motion picture films to ascanning operation, starting each succeeding film while the precedingfilm is still in motion, so that both films then move simultaneously,transmitting the images on the films by electrical currentsrepresentative of said scanning, synchronizing the movement of the twofilms during this period of simultaneous motion, adjusting during thesame period the phase position of the image of the succeeding film to bein the same phase as the image of the preceding film, and discontinuingtransmission of the preceding film and beginning transmission of thesucceeding film at a predetermined distance from the end of saidpreceding film.

6. The method of televising an animated scene comprising the steps ofsuccessively and continuously producing aplurality of motion picturefilms from said animated scene, immediately subjecting each filmsuccessively while in motion 'to a scanning operation, and transmittingthe images on the films by electrical currents representative of saidscanning, starting each succeeding film while the preceding film isstill in motion so that both films then move simultaneously,synchronizing the movement of the two films during the period ofsimultaneous motion, adjusting during the same period the phase position of the image of the succeeding films to be in the same phase as theimage of the preceding film, and discontinuing transmission of thepreceding film before reaching the end thereof and simultaneously takingup transmission of the succeeding film.

GEORG SCHUBERT.'

